DES MOINES, Iowa (AP) — Sen. Joni Ernst of Iowa repaid $1,900 to the Office of Tax and Revenue two days after a newspaper questioned her about a tax break she had been claiming on her condo in Washington for years.

Ernst wrote a check for the agency's Washington, D.C., office last week, according to the Des Moines Register , which brought the issue to attention of the first-term Republican.

Brendan Conley, the senator's spokesman, said the homestead tax credit claim was made in error and that Ernst immediately returned it when she learned of the mistake.

The credit only applies to a homeowner's primary residence, and Washington's homestead tax application instructions specify that Congressional members are generally ineligible.

Ernst had claimed the exemption for her Washington condo and her home in Red Oak, Iowa, since 2016, public records show. Ernst and her ex-husband, Gail Ernst, saved at least $308 in property taxes through the Iowa exemption, according to records.

Ernst's office didn't respond to the newspaper's questions about how the error occurred. But Ernst's letter to the Office of Tax and Revenue said the agency has been sending information about the tax deduction to an incorrect address.

"Senator Ernst clearly violated the law by seeking multiple homestead deductions," said Amelia Penniman, a spokeswoman for American Bridge 21st Century, a liberal super PAC that tracks Republicans. "Millions of Iowans pay their taxes on time under penalty of law. Why is it that Senator Ernst will only pay hers when she's caught red-handed?"

American Bridge identified Ernst's improper tax deduction and provided the records to the newspaper.

It's unclear if Ernst will face any penalty for the claim. She's planning to run for a second term in 2020.